Build Your Own Combat Robot

FIGURE 10-11
Robot with a
spinning drum in
front of the robot.
Chapter 10: Weapons Systems for Your Robot 227
Drum robots are typically made in a four-wheeled configuration, with a
roughly square overall shape. The wider weapon doesn’t need much careful aiming
to use effectively; and because the impacts of the weapon tend to lift the target robot
into the air, the drum functions well in a ramming/pushing mode—repeatedly
kicking its opponent across the arena with a combination of weapon hits and
drive power.
Figure 10-11 shows a drum robot.
The vulnerable parts of the drum are the drive mechanism and support structure.
The simplest and most common design is to support the drum with bearing
blocks on either side and to use a chain drive to run the drum from a motor inside
the main body of the bot. This method works until a strong blow to either front
corner breaks a support arm, cracks a bearing block, or dislocates the chain.
Hiding the drive motor inside the drum is a more durable but much trickier option.
Because the drum will be subjected to a major downward impact every time it
strikes an opponent, support arms or wheels under the drum weapon to keep it from
being driven into the arena floor are a good idea. Many drums also have some
kind of ramp or scoop built into the drum supports, so that wedges will be fed up
into the drum—rather than getting under it without being hit.
The drum doesn’t pack nearly as much inertia in its weapon as the vertical spinner.
What inertia it does have can be maximized by constructing the drum with as